Posteromedial Corner (PMC) Injuries

Posteromedial corner injuries can result from twisting injuries, causing the knee to buckle and gap open on the inside of the knee.  Posteromedial corner injuries can also result from contact injuries, like a blow to the outside of the knee, that cause valgus gapping. Medial-sided injuries are very common with almost 750,000 injuries occurring every year in the United States. Overall, MCL tears are two to three times more common than ACL tears.

Symptoms depend on the severity of the injury. A mild injury (grade I or II) might present with pain over the ligament attachments. In more severe cases, patients feel that their knee can give out or buckle. Below are some of the most common symptoms of a PMC injury: 

• Pain: Pain on the inner side of the knee is a common symptom of a PMC injury. The pain may range from mild to severe, depending on the extent of the injury.
• Swelling
• Stiffness: The knee may become stiff, making it difficult to fully bend or straighten the leg.
• Instability: An individual with a PMC injury may feel that the knee is unstable, as if it’s “giving way” or unable to support their weight properly.
• Bruising: Bruising can develop around the site of the PMC injury, and the discoloration is often seen on the inner side of the knee.
• Difficulty Walking: Walking may be uncomfortable or painful, particularly if the PMC injury is severe.
• Popping or Clicking Sensation: Some people report a popping or clicking sensation when the injury occurs, which may be followed by pain and swelling.

A combination of a comprehensive physical examination, special x-rays, and an MRI are usually very accurate. Dr. Jorge Chahla and his team will perform a physical exam that will include testing your knee in an extended (straight) and flexed position to determine the location and severity of the injury. If the knee gaps in extension that is usually a more severe injury.  A special x-ray, called a valgus stress x-ray, will likely be obtained. This special x-ray allows Dr. Chahla to objectively quantify and diagnose (based on validated systems) a posteromedial corner injury with millimeter accuracy. An MRI will allow Dr. Chahla to further evaluate the extent of the MCL injury as well as to evaluate the knee for any concomitant ligament, meniscal, or cartilage injuries.